612 ] SUMMARY OF CURRENT RESEARCHES RELATING TO { 



the same idea. Ultimately, withi the collaboration of iM. Nachet, 

 Moitessier's design was reconstructed and improved. The arrangement, 

 viewed from behind, is seen in fig. 89. The stage, composed of a plate 

 ER perforated by an aperture, is applied on the stage of the Micro- 

 scope, and can-ies the oscillating system formed of an axis pivoting 

 around 0, and bearing the oscillating stage PP with its screw-supports 

 C. Behind, the axis is traversed by a horizontal bar BB, carrying at its 

 extremities two screws C intended to limit the movement of oscillation, 

 which can be controlled in advance by an index marking on a drum 

 the degree of displacement. A screw A can lower the stage below the 

 axis of rotation so as to neutralise the thickness of the object-glass. In 

 using the apparatus it is first centred with the help of a disk, which is 

 pierced by a small hole, and which has to be applied in the central 

 aperture. The disk is then replaced by the preparation, and the screw 



mr 



C-^ 



i ;ii 



mmc 





mmmam 



»''"js' 



Re 



- ,- T 



mni 



nnmc 



1 



IB 



"/;vrXW,:'^'':-,-:r:,:-y,vwv'/,v/(!(',va2aR 



Fig. 89. 



A regulated to such an extent as to reduce to a minimum the lateral 

 displacement of the object-glass in the movement of oscillation. The 

 stage is then inclined alternately on each side, and photographs taken. 



Microscopical Observations at High Temperatures : Gas-heat 

 Condenser and Air-Cooling Apparatus.*— The apparatus referred to 

 above is due to 0. Lehmann of Karlsruhe, and completes the adaptation 

 of his crystallisation Microscope to projection purposes. The firm of 

 Carl Zeiss supply these auxiliaries in such a form that they can be 

 immediately fitted to their ordinary Microscopes, which are then suitable 

 both for subjective observation, for the projection of the formation of 

 fluid crystals, and for observation of heated preparations. The Gas-heat 

 condenser (fig. 90) is inserted with the push-tube (a) into the push- 

 coUar of the Abbe illuminating apparatus under the Microscope, in 

 lieu of the ordinary condenser, and then clamped. It consists of : the 

 polariser (i) ; the iris diaphragm ; the illuminating lens ; the gas-burner 



Special Catalogue, Carl Zeiss (Jena), 1906. 



